The present invention relates to a needle protection arrangement for a hypodermic syringe.
The needle protection arrangement of the present invention is being adaptable for co-action with a hypodermic syringe that includes a container, a plunger which can be moved reciprocatingly in said container by means of a rod and a needle which is affixed to or fastenable to one end-part of the container.
The invention is further based on said needle protection arrangement having a needle protector, basically in the shape of a tube, usually a circular, cylindrical tube whose axial length is slightly greater than the length of the needle.
More particularly, the present invention is devised for use with a needle protector in which the tube has an inner, radial-related cross-section corresponding to, or at least essentially corresponding to, an outer, radial-related cross-section for the container.
This cross-section dimensioning of the needle protector enables the device to be arranged for axial movement in relation to the container from a position in which the needle is covered by the device to a position in which the needle is exposed or vice-versa.
The invention relates more especially to such a needle protection arrangement in which the tubular needle protector""s axial movement relative to the container can offer two distinctly separate setting positions, a first position in which the needle protector is devised to protect the needle and its point, the free end of the needle protector or tube end located next to the needle point, and a second position in which the needle protector is devised to protect the needle and with the free end of the needle protector or tube end located at a greater distance from the needle point while the needle protector covers the needle and its point, the first setting position being devised to initially pose stiff resistance to movement of the needle protector in relation to the container.
There has long been a wish to protect people who handle hypodermic syringes, used for injection and/or aspiration, against accidental injuries (prick injuries), and several different designs of needle protectors have been proposed to this end.
These needle protectors are usually movably or removably mounted to the container of the syringe and have an elongated shape enabling them in one position to cover the needle and the needle point.
The needle protector is removed prior to injection and/or aspiration so as to expose the needle and its point.
For the sake of simplicity, the following description is solely concerned with the injection of liquids, although it will be understood by anyone well-versed in the art that the concept xe2x80x98injectionxe2x80x99 is equally applicable to aspiration.
A needle and needle point which remain exposed after an injection could become contaminated and thereby transmit serious illness to a person who is accidentally injured by the exposed needle and its needle point.
Various types of needle protectors which protect people against accidental injury are known to the art. Such protectors are basically in the form of a tube with a protective seal on the tube""s free end.
A needle protector of this kind will have the form of a sleeve which can readily be removed from the syringe immediately prior to an injection. This sleeve must be kept separate during the injection process. After the injection the needle protector must be replaced by hand over the needle so as to shield the needle against unintentional contact therewith.
A needle protector sleeve of this kind is dimensioned at its open part for a secure but easily released co-action with the part of the needle attached to the container.
Other known needle protector constructions are movable over the container and co-act therewith during the injection, the injection syringe and the needle protector then forming a unit.
The present invention relates to the latter category of needle protection means.
Earlier known hypodermic syringe constructions with associated needle protection have been described and illustrated in the following patent publications:
U.S. Pat. No. 4,425,120 illustrates and describes a needle protector (19) which, in a first position, covers the needle (15) and the needle point (25) and, in a second, upwardly moved position, exposes the needle and the needle point.
The needle protector (19) is tubular which, at its free end, has a hole (41) large enough to allow a needle-holding means (24) or a needle protector (29) to pass through the hole.
The hole (41) may be covered with a material that is punctured by the needle (15) and/or the needle protector (29). The covering material is devised as a sealing end-region of the tubular needle protector and serves to seal the end-related edge or end surface of the tube.
U.S. Pat. No. 2,571,653 illustrates and describes a needle protector (1) which can be moved reciprocatingly between fixed positions, i.e., between a needle covering position and a needle exposing position. The free end of the needle protector (1) is conical and has a central opening which is devised to enclose the needle attachment (4).
The needle protector shown in U.S. Pat. No. 4,725,267 has an opening, i.e., a hole (58), and the free end (56) of the needle protector (60) is devised to correspond to the needle (14) cross-section.
A needle protector of the initially cited kind, described and disclosed in the international patent application no. PCT/SE98/01673 (WO99/17822), is also known.
More specifically, the invention relates to a construction in which the axial movement of the needle protector or tube in relation to the container has two distinct, separate setting positions, i.e., a first position in which the needle protector is devised to protect the needle and the needle point and with the free end of the needle protector located next to the needle point, and a second position in which the needle protector is devised to protect the needle and the needle point and with the free end of the needle protector located at a greater distance from the needle point while the needle protector covers the needle and its point, the first setting position being devised to initially pose stiff resistance to movement of the needle protector in relation to the container.
The contents of patent publication U.S. Pat. No. 4,801,295 are especially part of the prior art.
This publication illustrates and describes a needle protection arrangement for a hypodermic syringe.
It describes a hypodermic syringe with a needle protector which can be moved along the syringe container in order to assume a normal, first position in which the needle protector surrounds and protects the needle.
The needle is at least partially exposed in a second position on the container.
In a third position, the needle protector is moved to a needle-covering position and is locked and so firmly attached that it effectively prevents re-use.
FIG. 1 shows a position in which the needle protector is in its first position, FIG. 2 shows a position in which the needle protector exposes the needle for use, and FIG. 3 shows the needle protector in a third fixed position.
FIG. 4 further shows locking for the first position according to FIG. 1, FIG. 5 shows locking for the second position according to FIG. 2 and FIG. 6 shows locking for the third position according to FIG. 3.
It can then be seen that the position according to FIG. 4 has a recess 54 with a sloping surface 56 to facilitate needle protector 42 movement in relation to the container 32 in exposing the needle 38.
In the corresponding fashion, the position according to FIG. 5 shows a cavity 60 with a sloping surface for providing relative movement, whereas FIG. 6 depicts co-action with straight wall sections 64 in order to enclose the part 52 in blocking and locking the needle protector in the lower position.
Utilization of two parallel guide grooves 48 and 50 are shown here. They require the needle protector to be rotated in relation to the container in order to move the needle protector from the second position in the upper part of guide groove 48 to the third position in the lower part of the guide groove 50.
When taking into consideration the technical deliberations that a person skilled in this particular art must make in order to provide a solution to one or more of the technical problems that she/he encounters, it will be seen that, on the one hand, it is necessary initially to realize the measures, and/or sequence of measures that must be undertaken to this end, and, on the other hand, to realize which means is/are required to solve one or more of the said problems. On this basis, it will be evident that the technical problems listed below are relevant to the development of the present invention.
When the prior art, as described above and particularly illustrated and described in the initially cited international patent applications, is considered, it will be seen that a technical problem resides in devising a needle protector arrangement posing initially stiff resistance to movement of the needle protector from a distinct first position to a needle-exposing position, and after completed injection being able to bring the needle protector to a distinct second position after an injection position, thereby locking the needle protector in this position to the syringe container.
It will also be seen with a needle protection arrangement in which a utilized needle protector can assume one of two or three setting positions in relation to a container, that a technical problem resides in producing with simple means conditions in which the needle point can be readily released and exposed and then, after an injection, being able to re-cover the needle point by locking the needle protector or tube to the container.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with only letting the said second position be devised to offer the said locking of the needle protector in relation to the container.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with equipping the needle protector with a specially shaped locking boss designed to co-act with a container groove/grooves or vice-versa in order, in a first position, to pose stiff resistance to movement of the needle protector to a needle-exposing position, and in movement to a needle-covering position to be able to pass the said first position in moving the needle protector to a second needle-protection position and at which the needle protector is locked to the container.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with having slightly bevelled edges, or at least bevels facing a defined direction relative to the movement, on a locking boss in the needle protector arrangement.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with having a container groove with bevelled edges, or at least bevels facing one direction relative to the movement, in the said first position.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with having a container groove with squared-off edges, or at least edges facing one direction relative to the movement, in the said second position.
It will also be seen that a technical problem resides in being able to realize the importance of and advantages associated with creating conditions in which the needle protector or tube and container become inseparably conjoined in the said second position.
It will also be seen that a technical problem resides in creating, with simple means, conditions in which attempts to defeat locking, when the needle protector arrangement is in its second, locked position, primarily causes the container to break at the first position.
It will also be seen that a technical problem resides in creating conditions in which the fracture line is located next to and preferably immediately under the plunger when the plunger is in its lowest position.
It will additionally be seen that a technical problem resides in creating conditions in which, after the container has fractured following an attempt to defeat the locking arrangement, one part contains the needle, covered by the needle protector and with the needle protector locked in its second position, whereas the second part constitutes the larger part of the container with the fracture surface covered in whole or part by the plunger.
The present invention takes as its starting point a needle protection arrangement for a hypodermic syringe, comprising a needle protector in which the needle protector is devised to co-act with a syringe with a container, a plunger capable of reciprocal movement inside the container and a needle affixed to or fastenable to one end-part of the container, the said needle protector basically having the shape of a tube whose axial length is slightly greater than the length of the needle and which includes the features cited in the introduction in other respects.
The invention is also based on the circumstance that axial movement of the needle protector or tube in relation to the container shall have at least two, separate, distinct positions, i.e., a first position in which the needle protector or tube protects the needle and its needle point, the free end of the needle protector or tube located next to the needle point, and a second position in which the needle protector or tube protects the needle, the free end-part of the needle protector or tube being located at a greater distance from the needle point, while the needle protector covers the needle and its needle point, the said first needle position being devised to pose stiff resistance to movement of the needle protector or tube in relation to the container.
With the intention of solving one or more of the aforesaid technical problems, it is proposed in accordance with the present invention that the tube devised as a needle protector be arranged so the said second position provides locking and inseparable conjoining of the needle protector or tube in relation to the container, and the needle protector or tube is provided with a locking boss.
According to proposed embodiments that lie within the scope of the invention concept, it is proposed that the locking boss have somewhat bevelled edges.
In said first position, the container shall be provided with a groove having bevelled edges.
The container shall have a groove with transverse edges in the said second position.
The needle protector or tube and container are inseparably conjoined in the said second position.
The invention also proposes that any attempt to forcibly remove the needle protector from the container, when they co-act in the second position, will cause the container to fracture and destroy its injection capability.
The invention also proposes that this fracture produces one part in which the needle point and needle are covered by the needle protector and accordingly encapsulated, whereas the other part comprises the container, the open end-part of which is sealed by the plunger.
The main advantage regarded as characteristic of an arrangement for a syringe according to the present invention is that it thereby creates conditions for making a needle protector, using simple means, readily movable along the container of a hypodermic syringe.
Sliding the needle protector from a first position along the container to expose the needle and needle point for injection shall be easy.
After the syringe has been used, sliding the needle protector over the needle point, past the said first position to a second position in which the needle protector serves as permanent protection, the needle protector and the container being locked and inseparably conjoined in that second position, shall be possible.
Fracture scoring creates prerequisites.
The primary characteristic features of a needle protection arrangement for a hypodermic syringe according to the present invention are set forth in the characterizing clause of the following claim 1.